Transparentizing compositions and process



Patented June 22, v1954 TRANSPARENTIZING COMPOSITIONS AN PROCESS RobertR. Parmentier, Upper Darby, Pa.

No Drawing. Application January 2, 1952, Serial No. 264,659

3 Claims. (Cl. 260-335) invention relates to compositions andprocesses'for transparentizing and sealing fibrous materials such aspaper.

It=is.often desired to reproduce copies of draw--ings,..printed..pages,.or other similar materials.

This. may be accomplishedby photographing the drawing 'and preparingprints from the so-cbtainedinegative. A further method is toprepareprints directly from such page or drawing. In this latter method, thepaper in general use is too opaque to permit the preparation ofsatisfactory prints, and'in the photographic process the cost of thereproduction makes the process prohibitive in :many instances. In orderto overcomethese .andlother.difficultieait has heretofore beensuggested...to employ various compositions in order to transparentizethepaper from which reproductions are desired, and thus render theattainment of prints directly therefrom feasible. Gompositionsheretoforeproposed, however, have serious": disadvantages which greatly restrictor prevent theiriuse. For example, compositions heretofore proposedsuffer one or more of the following difficulties: the compositions maybe dangerousto compound and use; are difficult to prepare and apply tothe paper; drying thereof isrslow; the material used intransparentizing, usually an oil, seeps, i. e., is transferred to printsand :other papers which it contacts thus restricting, its use andmakingstorage'of the treated paper difficult; odor is imparted to thetreated paper which makes its use obnoxious and which permeates otherpapers and materials such as when-stored together; the treated papertacks, i..e. the treated paper sticks to hot surfaces of reproducingmachines, which prevents or greatly limits their use in most processes;and the treated paper is not sufficiently transparentized, or isunevenly transparentized, so that suitable reproductions cannot beprepared therefrom.

In patent application, Serial No. 155,565, filed April 12, 1950, nowPatent Number 2,616,815 a transparentizing solution comprising mineraloil, 10-35 vol. per cent; toluene, 4-10 vol. per cent; and carbontetrachloride, 55-80 vol. per cent is described. As further described insaid patent application, and as claimed in patent applications, Serial.Numbers 190,882 and 190,883, filed Qctober 18, 1950, now Patent Numbers2,646,363 and $2,646,369 respectively, it is preferred to applyausealingcomposition, comprising wax, 2-6 vol. per cent; a gasolinehydrocarbon fraction, 31-47 vehper cent; and carbon tetrachloride, 47-67vol. per cent; topaper transparentized by the aforementioned:transparentizingsolution to prevent seepage.

An object of the present invention is to provide compositions effectiveto transparentize and seal .paper which obviates the difiicultiesencountered' with heretofore known compositions. A further object is toprovide compositions effective to transparentize and seal paper with asingle application. Another object is to provide a process forsimultaneously transparentizing and sealing paper.

The novelcomposition of'the present invention comprises mineral oil,10-35 vol. per cent; benzene, toluene or xylene, 4-10 vol. per cent;carbon tetrachloride, 55-80 vol. per cent; and a small soluble quantityof synthetic rubber. This composition is applied directly to the paperto be transparentized, preferably to the side thereof which does notcontain the printed matter or drawing, the reproduction of which isdesired. Application is conveniently accomplished by rubbing the paperwith a cloth or sponge saturated with .the transparentizing and sealingsolution. Other means of application may be employed, such as spraying,brushing, and dipping. The composition of the present invention dries ina very short time, within about 1-5 minutes, and the so-treated papermay then be used in preparing photographic reproductions.

An advantage of the composition of the present invention is that .thepaper is transparentized and sealed by application thereto of a singlesolution, 1. e., the application of a separate sealing composition isunnecessary.

The oil employed in the present composition is preferably a refinedwhite mineral oil boiling in the lubricating oil range. The aromaticcomponent maybe benzene, toluene or xylene, usually as a mixture ofxylenes, or a mixture of two or all three of the named aromatichydrocarbons.

The synthetic rubber to employ must be soluble in the liquid componentsto the extent of at least 0.075 gram per 100 cc. of solution. Polymersof chloroprene, copolymers of butadiene an styrene, and copolymers ofchloroprene and isoprene are examples-of synthetic rubbers which givegood results. Natural rubber and polyvinyl chloride are not sufficientlysoluble in the liquid components of the composition to warrant theiruse.

It is important that the stated concentration ranges for theingredients-of the present compositions be observed. If mineral oil beemployed in less than the stated amount, the paper is not suflicientlytransparentized to permit satisfactory reproduction, whereas if morethan the slow drying and seepage occurs; if less than the 3 statedamount of aromatic, such as toluene, is employed seepage is observed,whereas if more than the stated quantity is employed the composition maybe inflammable and have an oflensive odor; if carbon tetrachloride isemployed in less than the stated quantity, penetration of the paper bythe transparentizing composition is decreased thereby making theapplication of the composition difficult, and the composition may beinflammable, whereas employing more 1 than the stated quantity resultsin too fast drying which makes its application to paper difficult anduneven. The synthetic rubber should be soluble in the admixture of othercomponents to the extent of 0.075 gram/100 cc., and the operable rangeis from 0.075 to 1 gram/100 cc., but it will seldom be necessary todissolve more than 0.3 gram/100 cc. Using concentrations of syntheticrubber lower than the minimum stated,

a good seal sufiicient to prevent seepage of oil is not obtained,whereas at concentrations above the stated maximum, tacking is observed,and in some instances the synthetic rubber may be removed from the papersurface by rubbing.

In the event that anti-oxidants or other foreign materials have beenadded to the synthetic rubber, the solution may exhibit a slight haze orcloud. In general, such haze or cloud does not deleteriously afiect thepresent process, but where using relatively high concentrations ofsynthetic rubber the haze may be objectionable. In such case, the hazemay be removed by filtration.

Various papers may be treated in accordance with the present process,and the so-treated papers used in various reproduction processes. Paperswhich may be treated, for example, include the usual bond paper of sayabout 13 to 24 lb. weight per 1000 sheets, photographic, tracing, chartand blue print papers, and in general any paper except very heavyfibrous materials such as cardboard. The treated papers may be employedfor making reproductions in a variety of processes involving thetransmission of light through the treated paper. As illustrative of suchprocesses may be mentioned direct printing such as contact box printing,the use of Ozalid, Bruning, blue print machines and actinic lightcontact printing. The treated papers may also be used in projectionprinting.

Example I A series of compositions in accordance with the presentinvention was prepared and tested.

Preparation was by dissolving synthetic rubber o in a solution ofmineral oil, 28.5 vol. percent; carbon tetrachloride, 66.5 vol. percent;and benzene, vol. percent. Synthetic rubbers used included threedifferent polymers of chloroprene, a copolymer of chloroprene andisoprene, and two difierent copolymers of butadiene and styrene. Eachsynthetic rubber was dissolved in concentrations of 0.075, 0.15, 0.30and 5.0 grams/100 cc. of solution; some compositions were prepared at0.5 and 1.0 gram/100 cc. concentration.

Photolith copies of engineering drawings on opaque paper unsuitable fordirect reproduction were transparentized and simultaneously sealed withthe above composition by rubbing the photolith back with a clothsaturated with the composition being tested. Prints were prepared fromthe transparentized and sealed drawings using a direct printing (Ozalid)machine. It was found that the synthetic rubbers were not sufiicientlysoluble at 5 grams/100 cc. to pre- 4 pare suitable solutions; thecompositions were colored, viscous, and could not be satisfactorilyapplied to paper.

At concentrations of 1 gram/ cc., such as when using a copolymer ofchloroprene, good transparency and sealing was observed, but thecompositions were relatively difficult to apply, were slightly tacky insome instances, and were not quite as translucent to light as theremaining compositions. Accordingly, use of compositions containing lessthan 1 gram/100 cc. solution is required.

At concentrations of 0.075, 0.15 and 0.30 gram/100 cc. excellent resultswere achieved in all instances. The compositions were easy to apply andtransparency was obtained. On storage in contact with other paper noseepage from the transparentized and sealed drawings was observed.Prints were prepared from transparentized and sealed drawings at each ofthe stated concentrations of synthetic rubber and excellent resultsobtained. None of the transparentized papers exhibited a detectableodor. However, at concentrations of synthetic rubber below the 0.075gram/100 cc. solution, a slight amount of seepage is observed.Accordingly, use of compositions containing at least 0.075 gram ofsynthetic rubber/100 cc. of solution is required.

Example II Another series of compositions was prepared identical to thecompositions of Example I except that toluene was substituted forbenzene. Three separate polymers of chloroprene were employed atconcentrations of 0.075, 0.15, 0.30 and l gram/100 cc. of solution.

Results substantially identical to those of Example I were obtained.

In both of the above examples, the paper treated was transparentized andsealed to substantially the same extent as when using both thetransparentizing composition and sealing composition of aforementionedpatent applications, Serial Numbers 155,565, 190,882 and 190,883.

Within the operable ranges of synthetic rubber concentration, thecompositions dry practically immediately on application to paper, sothat printing may be begun within 1 to 5 minutes after application.

Natural rubber is not soluble in the present solution to the extent of0.075 gram/100 cc., and hence is not operable. Copolymers prepared fromadmixtures containing substantial quantities of acrylonitrile andpolymers of vinyl chloride likewise are not suiiiciently soluble towarrant their use in the compositions of the present invention.

I claim:

1. A transparentizing and sealing solution consisting of from 10-35 vol.per cent mineral oil, from 55-80 vol. per cent carbon tetrachloride,from 4-10 vol. per cent benzene, and from 0.075 to 1 gram per 100 cc. ofsolution of a synthetic rubber selected from the group consisting ofpolymers of chloroprene, copolymers of butadiene and styrene, andcopolymers of chloroprene and isoprene.

2. A transparentizing and sealing solution consisting of from 10-35 vol.per cent mineral oil, from 55-80 vol. per cent carbon tetrachloride,from 4-10 vol. per cent of a material selected from the group consistingof benzene, toluene and xylene, and from 0.075 to 1 gram per 100 .00.

of solution of a synthetic rubber selected from the group consisting ofpolymers of chloroprene, copolymers of butadiene and styrene, andcopolymers of chloroprene and isoprene.

3. Process for transparentizing paper which comprises applying asolution consisting of from 10-35 vol. per cent mineral oil, from 55--80v01. per cent carbon tetrachloride, from 4 10 vol. per cent of amaterial selected from the group consisting of benzene, toluene andxylene, and from 0.075 to 1 gram per 100 cc. of solution of a syntheticrubber selected from the group con- References Cited in the fi1e Of thispatent UNITED STATES PATENTS Number Name Date 1,233,334 Fehringer July1'7, 1917 2,400,612 Sprague May 21, 1946 2,495,135 Rodman Jan. 17, 1950

1. A TRANSPARENTIZING AND SEALING SOLUTION CONSISTING OF FROM 10-35 VOL.PER CENT MINERAL OIL, FROM 55-80 VOL. PER CENT CARBON TETRACHLORIDE,FROM 4-10 VOL. PER CENT BENZENE, AND FROM 0.075 TO 1 GRAM PER 100 CC. OFSOLUTION OF A SYNTHETIC RUBBER SELECTED FROM THE GROUP CONSISTING OFPOLYMERS OF CHLOROPRENE, COPOLYMERS OF BUTADIENE AND STYRENE, ANDCOPOLYMERS OF CHLOROPRENE AND ISOPRENE.